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US 4,405,785 AGranted
Vat dyestuff prepared from crude anthraquinone mixtures
AssigneeToms River Chemical Corporation
InventorsJoseph W. Fitzpatrick, Harold N. Schmidt
Life of this patent
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Abstract
Useful vat dyestuffs can be prepared by reacting a mixture of aminoanthraquinones containing 65-80% 1-aminoanthraquinone and 20-35% of a mixture containing 2-aminoanthraquinone and 1,5- and 1,8-diaminoanthraquinones with, for example, a halogenated benzanthrone or anthraquinone. The mixture of aminoanthraquinones can be obtained by nitrating anthraquinone in sulfuric acid and thereafter reducing the resulting nitroanthraquinones.
Claims3
A process for manufacturing a vat dyestuff comprising the steps of (1) nitrating athraquinone in the presence of sulfuric acid;
- (2) reducing the crude nitration product from step (1) to give a crude mixture of aminoanthraquinones which is 65-80% 1-aminoanthraquinone with the rest being a mixture of 2-aminoanthraquinone, 1,5-diaminoanthraquinone and 1,8-diaminoanthraquinone;
- (3) condensing the crude mixture of aminoanthraquinones from step (2) with a halogenated benzanthrone;
- and (4) ring closing the crude condensate of step (3) to give a vat dyestuff which is of substantially the same shade and dyeing strength as a vat dyestuff obtained by condensing the halogenated benzathrone with substantially pure 1-aminoanthraquinone and ring-closing the resulting condensate.
Dependencies are inferred from the claim text.